Fluid pressure apparatus



Jan. 3, 1933. 1.. F. WHITNEY FLUID PRESSURE APPARATUS Filed Dec. 17, 1930 6 Sheets-Sheet 2 Inventor Jinan It: 'i

Aiijysh Jan. 3, 1933.

| F. WHITNEY.

FLUID PRESSURE APPARATUS 6 Sheets-Sheet 3 Filed Dec. 17} 1930 tor ' #569. A figs.

Inven L man. W by Jan. 3, 1933. L. F. WHITNEY 1,892,823

FLUID PRESSURE APPARATUS Filed Dec. 17, 1930 6 Sheets-Sheet 4 my. I].

In ventor."

L. F. WHITNEY FLUID PRESSURE APPARATUS Jan. 3, 1933.

Filed Dec. 17, 1930 6 Sheets-Sheet 5 Inventor. an W/ZL' 6 A lftyo Jan. 3, 1933.

F. WHITNEY FLUID PRESSURE APPARATUS Filed Dec- 17. 1930 6 Sheets-Sheet 6 ZZIIIIIIIZREW a v ga -Eg a EEEEE H J v Invent m'aurzi 'z 9222 Patented Jan. 3, 1933.

UNITED STATES- ra'r'srrr OFFICE.

LWM E. WHITNEY, Q1! BOSTON, MASSACHUSETTS, ASSIGNOB TO COMSTOGK dz WESGOTT, 13:30., BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS rLuIn r can mares hpplication filed December 17, 1930. serial 1W0. 508,006.

This invention relates to an improved heat exchange system and method, and more particularly to a refrigerating apparatus and method employing circulating propellant and refrigerant fluids...

United States Patent No. 1,761,551 to Eastman fi'eaver, dated June 3,1930, discloses a system of this eneral type (which preferably employs a re atively heavy and nonolatile propellant such asmercury, and a light- .er and more vo-atile refrigerant such as water. My patent No. 1,761,553, issued June 3, 1930, and my application Serial No. 269,712, filed April 13, 1928, disclose apparatus of this general character in which the propellant may he efiective in pumping the refr gerant in a plurality of stages, while the last identitied application also discloses such a system in conjunction with a cooler which is disposed above the other component elements of the apparatus, means beingprovided to pump condensed refrigerant from the rer'rigerant condenser to the cooler. The copending application of Daniel F. Cornstock, No.

, 5023955, filed on even date herewith, discloses an improved system of this general type in which a portion of the circulating refrigerant may be employed to lift the condensed propellant above the propellant con-.

, denser or condensers to the top of a boiler return pipe. v Thus this arrangement permits the system to be relativel compact. and yet to have a relatively hi h boiler pressure, which may be balanced y a column of the propellant within the return pipe.

One aspect of the present invention relates to the provision of a system (if this general character having an improve arrangement for-supplying fluid, such as refrigerant to hit another fluid,such as the propellant in this manner, and preferably afierds an auxiliary pump arranged positively to su ply refrigerant to the propellant lifter, an arranged so that operation of this lifter is assured whenever operation of the system is. M initiated. The pump preferably may be self-' regulating so that its capacity is automatically varied in accordance with the requirements of the lifter, and so that further sup ply of refrigerant to the lifter may be interrupted under unusual operating conditions. The secondary or auxiliary pump may be arranged to entrain bodies oi condensed refrigerant between propellant globules and to successive globules of the propellant, and to lift the sameto the upper part of the propellant'returm pipe. A portion of the propellant thus lifted may be shunted from the main propellant circuit and is employed to exhaust non-condensable gases from the system, thereby permitting the continued 0 eraticn ofthe system at a low or sub-atmosp eric pressure. Apparatus of this general character is disclosed for example, in my copending application, Serial No. 174,212, filed March 10, 1927', as well as in my application, Serial No. 269,712, referred to above. Preferably the shunted propellant after passing through the evacuating means or purger passes to the secondary pump which supplies the refrigerant to the secondary boiler and propellant lifter, and then may pass to another pumping means which. is efiective in lifting the condensed refrigerant to a cooler l Fig.2 is an end elevation of a portion of the assembly with parts broken away;

Fig. 3 is .a sectional view of an aspirator assembly and a propellant condensing funnel Fig. 4 is a broken dia the cooler and related piping; Fig. 5 is an elevational view of the vaporizer, burner and relating parts;

ammatic view of p one of the propellant vapor ducts between the boiler and aspirator nozzle;

Fig. 10 is a view partly in section and partly in elevation of a separating chamber assembly that is associated with the refrigerant lifter;

Fig. 11 is a top view of the refrigerant condenser;

Fig. 12 is a sectional detail of the ropellant metering or dividing factor, wliich is effective in dividing the propellant stream to return a part of the lifted propellant directly to the boiler and to divert a part of the same to the purger, secondary pump, and refrigerant lifter;

Fig. 13 is an end elevation of the refrigerant condenser showing related piping and with a part broken away;

Fig. 14 is a section on line.14-14 of Fig. 10; and

Figs. 15, 16, 17, 18, 19, and 20 are diagrammatic views ofthe secondary pumping means under different conditions.

In accordance with the present invention, a. propellant fluid may flow about a propellant circuit which includes a boiler, while a. lighter and more volatile refrigerant may flow about a refrigerant circuit which has a part or parts in common with the propellant circuit, where the propellant is efi'ective in causing the circulation of v the refrigerant. Preferably separate refrigerant and propellant condensers may be associated with the propellant and refrigerant circuits, while a cooler may be disposed in the refrigerant circuit, and if desired may bedisposed at a level substantially higher than the common parts ofthe circuits and'the refrigerant condenser. In the case of a multi-stage system, the propellant system preferably includes parallel portions where energy is imparted from the propellant vapor to successive-portions of the circulating refrigerant stream. While a system of this general character may employ many types of working or circulating fiuids,'a heavy liquid of comparatively high boiling point, such as mercury, is preferred as the propellant, and a lighter more volatile refrigerant such as water ispreferred as the refrigerant. With an arrangement of this character, it is only to employ two liquids, not only in the main circuits of the system, but in all of the'auxilia'r circuits thereof, such as the propellant an refrigerant lifters, the purger, the secondarypumpnected to outlet pipes 15 which extend to the aspirator nozzles 19 and 19, each of these outlet pipes includes an expansible-contractible element 17, such as a metal bellows, the latter permit the expansion and contraction of the parts adjoinm the boiler to occur without throwing un ue strain upon aspirator nozzles 19 and 19. Preferably these nozzles may be formed of comparatively thin .material which is a relatively poor conductor of heat, such as nichrome, and they may form the sole direct connections between ,the ducts 15, which normally contain hot propellant vapor, and the ad'oining portions of the system, which prefera ly are maintained at a lower temperature. I

Ducts 15' also include frusto-conical portions 9 (Figs. 5 and 9) containing frustoconical screens 10 which are adapted to prevent the passage of foreign particles to the aspirator nozzles. The lower parts of screens 10 may be connected to thimble-like shells 13, each of which contains a central partition 14, with its lower edge somewhat spaced from the bottom of the shell. The frusto-conical portion of each duct 15 is inclined and an openin 8 is provided in the upper side of each she I 13. A closure plate 11 is disposed above the half of the shell ad'oining o enin 8 so that a trap is provided for t eco ection of condensed propellant which may pass about the lower edge of partition 14 and out of the o ning 8 and thence return to the boiler. "s arrangement permits condensed propellant to return to the boiler without necessitating its assage through the relatively finely mes ed screen elements 10 which would'afiord a comparatively high resistance to the passa e of giobules of hquid pro llant, especially if t e surface-tension oft e pro llant is high.

The pro llant, for 'examp e mercury, is

vaporized 1n boiler 1 and passes upwardly by a duct 21 with the cooler refrigerant vapor in chamber and thus causes evaporation of the refrigerant in the cooler. The mixture of propellant and refigerant vapors passes from mixing chamber 20 to funnel 25, which is aligned with nozzle 19; Fig. 3 illustrates more specifically this portion of the apparatus, the funnel having a portion of restricted diameter spaced from the mixing chamber and preferably having a general downward inclination therefrom. Suitable cooling means, such as tins 26, are associated with the tunnel to efi'ect the condensation of the propellant Vapor at its com- Sal paratively high temperature of liquetication, as the energy of the same is exhausted in compressing the refrigerant vapor.

Since the temperature of tunnel is well alcove the temperature of condensation ot the refrigerant vapor at the pressure conditions prevailing in this part of the system, the retrigerant vapor passes out of the funnel through the upwardly extending duct 30, a continuation of which is connected to the second stage mixing chamber 20 1 The propellant vapor in this mixing chamber is edective in further compressing the refrigerant and pumping the same into the tunnel 25 which is aligned with nozzle 1.9 lln general the nozzles, mixing chambers, and'funnels tor the two stages may be same eneral type, but preferably the mixing chain er tor the second stage pumping means is arranged so that the funnel 15-is disposed somewhat closer to the outlet of nozzle 19* than is the case with the corresponding parts or the first sta e aspirator assembly.

uitable drains are provided to receive the condensed propellant from the mixing chambers and tunnels, for example, the drains 31 and 31 may be connected to the lower parts of the mixing chambers to collect any particles of propellant which may have condensed in these parts of the apparatus, while drains 32 and 32 may be connected to the lower portions of the inclined funnels to collect the major portion of the condensed propellant from the same and from the adjoining refrigerant vapor ducts.

A refrigerant vapor pi e 36 from the second stage aspirator funne 25 preferably extends upwardly to a refrigerant condenser which is designated in 3 general by the numeral 40. Figs. 11 and 13 illustrate refrigerant condenser in greaterdetail; it comprises similar narrow tank sections 34, the pipe 36 being joined to the side of one of these sections intermediate its height. Preferably each of the sections 34 is formed of two similar sheet metal elements which are dished and provided with perimetric flanges 41 wh ch are welded to each other. At the ends of the condenser, suitable plates 42 arejoined to ends ofthe flanges 41and hold the sections 34 in proper spaced relation to each other. Both of these -sections have bottom portions extendin downwardly to outlet pipes 37 and 38 whlch are joined to a common refrigerant receiving duct 38. The tank sections 34 may each be provided with suitable heat dissipating fins 39, and their ends communicate with each other through a short connect'ng duct 41 The drain 31 may conveniently be joined to the drain 31, the latter extending downwardly to a main propellant collecting duct which is disposed adjoining the boiler 1. The upper end of a downwardly extending pipe 45 communicates with the drain 32 below its connection with tunnel 25, and the lower part of drain 32 provides a U-shaped trap which is connected to pi e 45 below its connection with drain 32. .he pipe 45 extends downwardly to provide .a trap 46 adjoining the lower part of the machine, the opposite leg of this trap being designated by the numeral 47 and extending upwardly to a pipe 70. A downwardly extending pipe 48 ot rel atlvely large diameter joins the upper part of pipe 45 with the propellant collecting pipe 50.

The secondary pumping means is designated in general by numeral 49 and includes the tube. 38 which receives refrigerant from condenser 40 and communicates with the upper part of the entraining chamber 51, Fig. 8. Mercury is supplied to the latter from one leg 52 of the trap 53, in-a manner which will presently be described. The major portion of duct 54 extending downwardly to a separating chamber 55 has a restricted internal diameter so that condensed refri crant passing downwardly throu h the same is entrained propellant which act as separate liquid pisions; thus the pumping means 49 may 1mpose a suitable pressure upon the refrigerant which passes out of the lower end of tube 54 into the separating chamber 55. .The upper end portion 54 of tube 54 may have a greater internal diameter than the remainder thereof, as shown.

A duct 56 has an open end in the upper part of chamber 55 and a duct 57 has an open end below ,the end of duct 56, but above that of tube 54, so that the lighter refrigerant rising to the upper part of the chamber normally passes into duct 56 and the heavier propellant normally-passes into duct 57 while the lower etweeri bodies or glo ules of the end oftube 54 is always submerged in propellant and-sealed against entry of refrigerant. A suitable by-pass duct 80 connects the entraining chamber 51 with the duct 57 be; low the separating chamber 55. Duct 56 is connected to one end of the upwardly extending duct 70 (Fig. 7) that communicates with a secondary boiler designated in general by numeral 71; this boiler is juxtaposed to flue 6 and comprises a small reservoir 72, which is connected to a tube 73 of restricted internal diameter having a plurality of helical windings disposed about the funnel 6 and forming an outlet for the secondary boiler. A continuation 7 4 of tube 73 is connected to an upwardly extending lifter tube 75 of restricted diameter which forms a cont-inuation of pipe 50. The end of pipe 70 which Is omcd to duct 56 communlcated w1th leg '47 of the trap 46, as previously described. It is evident that the refrigerant entrained in the tube 54 normally separates from the propellant in the separating chamber 55 and passes through pipes 56 and 70 to the reservoir 72. The latter is in direct heat trans fer relation to the flue 6, and accordingly the refrigerant is vaporized in this part of the system either in the reservoir or the tube 70 or the tube 73; the latter affords a considerable frictional resistance to the rapid flow of the refrigerant vapor, and accordingly the so uantity of vapor, which may thus flow t rough the secondary boiler 71 is restricted. The vapor passing into tube 75 breaks off mercury bodies and is effective in lifting the same through tube 75 to a separating 25 chamber. 82. An inclined pipe 83 (Fig. 13) connects the upper portion of the latter to the refrigerant condenser so. that the refrigerant vapor received from tube 75 may pass into the refrigerant condenser, there rejoining the main refrigerant circuit and being condensed.

The liquid propellant passes from the bottom of chamber 82 into a trap 183, a continuation 84 of which is joined to a propellant dividing factor 100. The latter is illustrated in greater detail in Fig. 12, and comprises an outer cylindrical shell 90 and an inner cylindrical member 91 of less height, the walls of the members 90 and 91 being spaced from each other and a sheet metal member 89, having spiral convolutions, being disposed between the members 90 and 91 and thus providin inner and outer spiral passages 92 and 93. e inner passage 92 communicates with the chamber 91*, which is above the member 91, so that mercury entering the chamber through pipe 84 ma pass downwardly through passage 92 an through an openin or notch 95 at the lower end of the shell, and thence upwardly through the outer spiral passe 93 which communicates with the duct 97 fi is evident that spiral passages 92 and 93 a-fi'ord considerable resistance to the flow of the mercury, and accordingly that the same tends to pile up above the member 91 and overflows intothe passage 101 in the central art of thelatter. Thus the factor 100 is e ective insupplying a fixed or limited 0 quantity of propellant to the purger through the duct 97 and in permitting the remainder of the propellant to pas downwardly through passage 101, which communicates with a propellant return-pipe 102. The latter is disposed adjoining the flue 6, and has its lower end commumcating with boiler through a connection 103, Fig.5. An opening 109 may be disposed in the upper part of the sheet metal element 89, to permit the pressures at opposite sides of the same to be equalized, and a suitable inwardly bent tab 106 is disposed ad Oinmg the mouth of duct 84 to prevent incoming mercury from passing directly to passage 101. The lower part of a gas-collectin chamber 120 is connected by a duct 122 with the refrigerant condenser so that non-condensable gases which occur in the system and are pumped to the refrigerant condenser may pass into chamber 120, While stray refrigerant that passes into chamber 120 may flow back to the refrigerant condenser. A pipe 111 for equalizing pressures connects chamber 120 with the upper part of the chamber 94 of the metering factor 100 and a pipe 123 joins ipe 111 with the entraining chamber 125 of the purger, Fig. 6. The chamber 118, which is connected to pipe 111, may contain a suitable connection for initially evacuating the system and a suitable sealing liquid for this connection, these parts being of conventional type and not being illustrated in detail. 1

Mercury from the factor 100 passes throu h pipe 97 to the entraining chamber 125 (Fig. 6). A tube 126 which includes a downwardly extending body portion of restricted internal diameter, has an enlarged upper end disposed within chamber 125. A suitable cylindrical screen 115 is arranged about the upper end of the tube, a closure plate 116 being disposed over the top of the member 115. An opening 117 may be provided in the side of the portion of pipe 126 that projectsinto the chamber. Thus mercury may pass into the pipe and flow down the same, due to its restricted internal diameter, in the form of successive liquid globules which entrain bodies of gas therebetween. The screen 115 is effective in preventing the clogging of tube 126 with foreign matter.

he successive lobules of propellant passing downward t rough the tube 126 serve to entrain and compress the non-condensable gases. The lower end of this tube is disposed concentrically within an outer pipe 127 which normally contains a mercury column, and an opening 129 in the tube 126 permits fluid to flow out of its lower end into the outer pipe. Due to the greater diameter of the outer pipe, the mercury and non-condensable gases separate; the latter bubbling upwardly throu h the mercury contained in the outer pipe; t e upper portion of the latter is connected to a chamber 128 which may be provided with a covering screen 129, and may communicate with the atmosphere; thus non-condensable gases may be exhausted to the atmosphere. It is evident that the atmospheric pressure upc the liquid mercury in pipe 127, plus the weight of that mercury is effective 1n balancing the internal presing therewit sures of the parts of the system communicat- A, pipe 130 is connected to the lower part of duct 127 receiving mercury therefrom and 5 delivering the same to trap 53, preferably an upwardly extendin continuation 130 of duct 130 is connecte to the entraining chamber 125, thus, acting as a byass should the tube 126 become clogged. ercury leaving the separating chamber 55 of the secondary pumping means 49 passes into tube 57, which comprises one leg of a trap 58, the opposite leg 58 of which is connected to an entraining chamber 150 that is disposed above the chamber 55. Chambers 125, 51, and 150 preferably may have the same general internal arrangement. Preferably the portion of trap 58 that is joined to chamber 150 may comprise a tube that is flattened to have an ovalor substantially elliptical cross-section, and this same expedient may be used in various other parts of the system to reduce the amount of mercury which is required properly to fill the propellant-containing parts of the system.

A drain 152 is connected to the refrigerant condenser above the outlets 37 and 38 and may be joined to the upper end of chamber 150; thus condensed refrigerant is preferentially supplied to the secondary pumping means 5:9 and thence to the secondary vaporizer 71 and the propellant litter. During normal operation of the system, however, the refrigerant in the condenser will not only 'filow to the secondary pumping means 49, but it will also pass through pipe 152 to chamber 150. "The lower portion of the latter receives the upper end of a tube 153 of restricted diameter, wherein propellant globules may entrain bodies oi the condensed refrigerant, subjecting the same to a considerable liquid head at the lower end of tube 153, which is joined to a separating chamber 155. The latter is shown in greater detail in Fig.- 10, the tube 153 having an open end disposed adjoining the bottom of this chamberand the refrigerant outlet pipe 158 communicatin' with the upper part of the chamber. Thus 't e li hter refrigerant separates from the props ant and passes upwardly through duct 158 under suitable pressure, so that it may be returned to the cooler 12 that is disposed above the remainder oi the system; or example, the mafor portion of the apparatus may be installed in the basement and the cooler may. be disposed within a refrigerator upon the diet floor.

As shown in Fig. 4, the bottom of the cooler preferably inclines downwardly to the tube 158 which is joined to the lowest corner of the cooler, so that stray propellant particles that pass into the cooler will flow downwardly through tube 158 and thus be received L by separating chamber 155. Preferably the lower part of tube 158 is flattened, being pro- 19, so that the refrigerant vided with such a shape and dimensions that mercury globules will not form in the same andclose its entire area so as to rise with the refrigerant. The open end of a duct 160 is disposed within chamber 155 at a height between the end of tube 153 and the month 158 so that mercury collecting in the of pipe lower part of the chamber will overflow into pipe 160 which forms one leg of a trap 161, the opposite leg of which is provided by the drain 32. Thus mercury will pile up in this I drain until it reaches the juncture of the same with pipe 45, whereupon the propellant flows into pipe l5, or, the latter being filled, into pi e 48 and thence to the main propellant co lecting pipe 50, while tube 153 having its lowerend always immersed in mercury,.is permanently sealed against blowing back of anp refrigerant due to fluctuating pressures.

referably the inclined bafies 17 0 and 171 may be disposed below and above the portion of pipe 30 that is located over'the propellant condensing funnels 25 and 25, (Fig. 2) so that air heated by these tunnels or the fins 26 will be diverted from this pipe and from direct impingement upon the fins of the refrigerant condenser 10; Furthermore, this arrangement not 0111 permits the more efiective cooling of the re rigerant condenser, but it also facilitates cooling of'the refrigerant vapor between the first and second pumping stages, so that the volume of the same that must be pumped may be somewhat reduced and aspirator eficiency in thesecond stage may be somewhat greater than otherwise would be possible in order to aid he adjoining the line, which is at a comparatively high temperature when the system is in normal operation. The flue and these pipes preferably are enclosed within a cylindrical casin 17G which may contain suitable powdere insulating material, such as iniusorial earth. A rectangular casing 261, also containing suitable heat insulating material may'enclose the lower part of the funnel; the mixing chambers, the propellant vapor ducts 15 and the boiler '1. Thus heat losses are minimized and the hot portions of the system are eflectively insulated. it is silocel or ice , thermal efliciency of the system the pipes and 102 are disposed its evident that the :funnels 25 and 25 project from the casing 261 and tion of the burner which is connected to the gas duct Bm'ay project from the wallet the casing (Fig. 5.)

In the operation of a system of this character, pro llant such as mercu iced in the ducts-15 to the separator nozzles 1 and 1 Vapor duct 21 permits refrigerant vapor to flow from cooler 12 to the mixing chamber 20 adjoining the outlet of aspirator nozzle is drawn from the cooler, thus causing the latter to have a low that the outer poris vapor iler1,passingupwar l throu h temperature and providing refrigeration.

he major portion of the propellant va or passing from the nozzle 19 is condense in funnel 25 and the refrigerant vapor passes through pipe 30 to the second sta e entraining chamber 20 where the nozz e 19 supplies additional propellant vapor to pum the refrigerant vapor through duct 36 to re rigerant condenser 40. The propellant condensing in funnels 25 and 25 passes into drains 32 and 32* and thence throu h ipe 48 to the main collecting pipe 50. T e rains 31 and 31 receive propellant which is condensed in the mixing chambers and are effective in supplying the same to the pipe 50. From drains 32 the propellant may ass directly through a portion of pipe to not 48 and thence to the main propellant collecting duct 50, it be ing understood that normally the leg 45 of the trap 46 is filled with mercury substantially to its juncture with pipe 48. Similarly mercury passing into the drain 32 normally will be received by the upper end of pi e 45 and thus pass to the pipe 48, since the ower part of pipe 32 is normally filled with mercu uring normal operation of the system refri rant is vaporized in the secondary boi er 71; the flow of this vapor is somewhat limited due to the restricted diameter of tubes 73, as it passes into the lower end of pipe 75, there being effective in breakin ofi successive globules of mercury and- 11 tmg the same to the separating chamber 82. The refrigerant vapor rises to the upper part of this chamber and passes from the same through pipe 83 to the refrigerant condenser, there rejoining the main refrigerant circuit. The propellant passes to the lower part of the chamber 82, being received by the pipe 83 and passing through its connection 84 to the saparatin factor 100. As hasalready been scribe this factor is efiective in tially diverting a portion of the li ed mercury to the purger tube 126, while the remainmg portion of the mercury or the propellant is returned throu h pipe 102 directly to the boiler; it being evident that the pipe 102 contains a liquid column of the propellant to balance the boiler pressure.

Mercury globules passing downwardly through tube 126 entrain non-condensable gases from the chamber 120, which is connected to the entraining chamber 125 of the purger by pipes 111 and 123. The purger will exhaust some refrigerant vapor from the system, especially if an insufficient volume of non-oondensable gases are supplied to the purger, it being understood, owever, that the amount of refrigerant thus exhausted will be no ligible even over a' long period of time. 1%1

mercury contained in the p1pe 127 may pass into the atmosphere, while the mercury passes upwardly through the pipe 130 to the trap 53 referene gases bubbling up through the,

and thence to the entraining chamber 51 of *the secondary pumping means 49. Liquid refrigerant is there received through pipe 38 from the bottom of the condenser 40 and is supplied to the separating chamber 55, thence passing through tube 56 and pipe 70 to the secondar boiler 71.

Accordingly 1t is evident that the umping means 49 is effective in supplying liquid refrigerant to the secondar vaporizer under an appreciable liquid hea due to the wei ht of the mercury globules in the tube 54. ercury passin from chamber into trap 58 is received ivy the entraining chamber 150 of the refrigerant lifter which is supplied with refrigerant from the condenser, and the mercury globules passing downwardly in tube 153 are efiective in im osing a suitable head upon the condensed re rigerant, so that the latter, when separated from the mercury in chamber 155, may'rise through tube 158 to the cooler, the mercury passing downwardly through trap 151 and filling the leg of the latter which is provided by drain 32 until it overflows into the upper part of pipe 45, thence passing to pipe 48 and the main collecting pipe 50 and in this way rejoining the main propellant circuit.

It is evident that all parts of the system are arranged so that stray propellant maybe returned to the ropellant containing part of the system. hus propellant passing to the refrigerant condenser may be received by the drains 37 and 38 and thus pass into the entraining chamber 51, while the cooler is so shapedthat stray mercury passing to the same will return through p1pe 158.

The secondary boiler 71 and related piping is arranged to insure proper operation of the pro ellant lifter'under all conditions. When t ere is a tendency for the pressure Within the secondary vaporizer to rise excessively thereby vaporizing much more of the refrigerant than is required for the proper operation of the lifter and thereby throwin an excessive load on the refrigerant con enser 40, the rise in ressure mentioned aforesaid causes a rise in the level of the mercury in pipe 54 of the secondary pumping means with consequent decrease of refrigerant fed to the vaporizer. Then the liquid in 72 vaporizes out of the vaporizer more rapidly t air water is supplied to it, whereby-the refrigerant retreats into tube 7 O and the rate of vaporization decreases, since the liquid refrigerant is no longer as near the flue 6. In consequence the pressure in the secondary vaporizer is lowered and more refrigerant is fed thereto, thus causing the level of the vaporizing surface to approach more nearly to flue 6 and in turn increasing the pressure and rate of vaporization to the end that the position of the refrigerant in the (vi akporizer alw ys tends toward a stable con- 1 Ion.

v53 and 58. The duct 38,

aaaaeas When the operation of asystem of this character is interrupted, for example, due to the stopping of'combustion in chamber 2, water will flow by its own gravity head from the lower part of condenser 40 through the tube 54 into pipes 56, 70, and the reservoir 72.

Mercury which might otherwise have interfered with this flow is afiorded storage space in duct 47 below tube 70, as the mercury in the legs 47 and tends to equalize when the flue 6 becomes cold. Mercury will also be contained in the lower part of the system, including the traps 46 and 161 and the pipe 50. Mercury will also be contained in traps the chamber 51 above the end of tube 54 and the tube 54, will be filled with water, as shown in Fig. 15, while mercury will fill the lower part of chamber 55 up to the mouth of duct 56 and. willfill duct 57 and the lower parts of bypass 80 and the duct 58.

Under these conditions, it the system is again started in operation by causing combustion to be resumed in chamber 2, there is a relatively large amount of water in direct heat transfer relation to the flue, and as soon as the temperature of the latter is raised, a slight vapor pressure develops in the secondary boiler 71, which will cause the tube 73 to become filled with vapor rather than liquid and mercury to be forced out of tube 74' into pipe 75, and the pressure in chamber 55 will rise, thus forcing the-mercury'level downwardly in this chamber and causing mercury to rise into the lower part of tube 54 and in the ducts 80 and 58* so that the secondary vaporizer pressure is balanced by the liquid heads in the tube 54, and ducts 80 and 58 (Fig. 16).

lln starting, until the flue 6 is suficiently heated, there will not be enough pressure available to cause the mercury to rise in tube 58 to spill over into chamber 150, and mercury which has come from the funnels and been lifted (as explained in the next paragraph) after passing through the metering device and purgerv will pass down tube 54 thereby pumping water into the secondary vaporizer; the mercury itself, as it cannot spill into chamber 150,1likewise passes down tube 55 into tube 47, spilling over from tube 45 intotube 48 and joining the main body of the propellant to be relifted.

The tube, 75 does, not aflord appreciable resistance to vapor flow at low velocity, 1. e., when the system is starting; accordingly, as the pressure continues to, rise in the secondary vaporizer, it'will be suficient to permit the vapor from tube 7 3 to be effective in breaking 0d a mercury globule in the lower end of pipe 75. Thus, mercury is lifted to the separating factor 100 which, as previously described, preferentially supplies mercury, upon starting, to the purger. Accordingly mercury soon passes from duct 130 into 7 increases, and mercury trap 153 and mercury flows from the upper end of duct 152 into chamber 51 and-is receivedby the .upper end of tube 54.v

When the first globules of propellant thus arrive at the upper end of the tube 54, the liquid head provided by these globules and the mercury in the lower end of tube 54 will tend automatically to balance the vaporizer pressure. If this pressure has not risen, the level of the mercury in chamber 55 may rise to the mouth of duct 56, as shown in Fig. 17, and as mercury continues to be supplied to the upper part of tube 54, the mercury may temporaril overflow into duct 56, passing downward y through pipe 47 into the lower part of the system. Under these conditions the mercury columns in tubes 58 and will remain at such a height as properly to balance the existent vaporizer pressure. As the system continues in operation, this pressure rises in spills over into chamber 150, while the mercury level in chamber 55 becomes lower so that it is substantiall in the region of the mouth of the drain 5 and so that mercury no longer passes into the duct 56. lithe pressure in the vaporizer rises still higher, water may pass fromthe upper part of c amber 55 into drain 57 so that the mercury is depressed in that drain by the water pressure thereabove and the efiective mercuryhead which substantially balances the vaporizer pressure will be greater than the dis tauce between the spill-over at the top of duct 58 and the mercury level in chamber 55 (Fig. 18). As the'vaporizer pressure thus rises andthe mercury head in trap '58 increases the proportion of mercury in the tube 54 will also increase so that the liquid heads will substantially ecpialize. Thus, means is provided automatica ly to reduce the amount of water entrained between mercury globules in the tube 54 as the vaporizer pressure increases, and accordingly less water is automatically supplied to the vaporizer as its pressure becomes greater. When the vaporizer pressure falls, the liquid heads in the pumping system automatically adjust themselves to balance the, lower pressure, and accordingly less mercury is contained in tube 54 and a larger pro ortion of water is provided in the same, t us 'a greater amount of water is pumped to the vaporizer whenever its pressure falls, and the water level moves nearer to flue -6, whereupon the vapor pressure tends to rise. 1

Should the pressure in the vaporizer approach a predetermined maximum, the proportion 0 mercury in tube 54 will increase until the mercury fills the tube up to the enlarged portion 54, and accordingly further flow of water through 54 is temporarily interrupted (Fig. 19). Such a condition will be reached just before the pressure upon the water in chamber 55 is sufliciently high to depress the mercu level in drain 57 to the juncture with the y-pass 80. If the pressure in the vaporizer still continues to rise, mercury will continue to pile up in the enlarged portion 54*" of tube 54 to balance this pressure and the mercury level in drain 57 will be further depressed so that the head in duct 58 may balance the higher pressure. This lowering of the mercury level in drain 57 results in the uncovering of the lower end of duct and permits water to flow from chamber 55 upwardly into the bypass 80, bubbling through the mercury in the by-pass and thus returning to chamber 51 at the upper end of tube 54 (Fig. 20). Accordingly, under' extreme vaporizing conditions water may be forced upwardly through duct 56, chamber 55 and thence through drain 57 and the by-pass 80 so that it returns to the chamber 51 above the tube 54, thus automatically permittin increase in the vapor-containing volume 0 the system in the region of the vaporizer so that the vaporizer pressure falls. In the meantime, the tube 54 will remain filled with mercury. When the vaporizer pressure has thus been relieved, the pressure upon the water in chamber 55 will become lower, the level of the mercury in drain 57 will rise, and the system will resume normal operation. Under all conditions, the lower end of tube 54 is immersed in a body. of mercury which acts as a seal and which prevents the vaporizer pressure from forcing mercur out of the tube.

rom the foregoing, it is evident that the secondary pumping means 49 provides an arrangement permitting the automatic formation' of a liquid head upon starting of the system which will balance the initial vaporizer pressure even before the first increment of mercury reaches the upper end of tubes 54 (Fig. 16); that the chamber 55 and its connections are so arranged that mercury may be drained from the same through duct 56 when the height of the mercury column in duct 58 is not suflicient to permit the mercury supplied to the secondary pumping means to overflow into chamber 150 ('Fig. 17) that thepressurebalancing head in duct 58" will automatically balance the pressure in chamber 55 which is dependent upon the vaporizer pressure andthat this arrangement permits the automatic variation of the amount of water supplied to the vaporizer in response to the vaporizer pressure. Accordingly, when the rvaporizer pressure reaches a' substantially predetermined point further su p11; of water to the vaporizer is interrupted ig. 19); while should the vaporizer pressure continue to rise even above this point,'automati'c means is provided for releasing water from the vaporizer and automatically increasing the vapor-containing capacity of the adjoining part of the system to relieve the vaporizer pressure (Fig. 20).

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall withiln the scope of the appended claims.

I c aim:

1. Apparatus of the class described comprising a vaporizer, a heating factor associated therewith, a condenser connected to the vaporizer, a secondary boiler adjoining the heating factor, said boiler including an enlongate passage of restricted cross section, a return pipe havin its lower end connected to the vaporizer, an a lifter pipe of restricted cross section adapted to receive liquid from the condenser and connected to the upper end of the return pipe, said passage being connected to said pipe so that vapor from the boiler lifts condensed fluid to the upper end of the pipe.

2. Apparatus ofthe class described comprising a propellant circuit, a refrigerant circuit, said first circuit including a vaporizer and condenser, said second circuit including a cooler and a second condenser, havin a part in common where vaporized prope lant pumps the refrigerant from the cooler to the second condenser, a propellant return duct having its upper end disposed above the first condenser and its lower end connected to the vaporizer, a secondary boiler arranged to receive refrigerant from the second condenser, said boiler comprising a reservoir and an elongate tube of restricted diameter, a lifter pipe of restricted diameter, the tube being connected to the lifter pipe, and means to supply the condensed propellant to the lower end of the lifter pipe, the upper end of the latter communicating with the return duct, whereby va or from the secondary vaporizer iraises t e condensed propellant to the upper part of the return uct.

3. Apparatus of the class described comprising a pro llant circuit including a propellant vaporizer and a pro llant condenser, a refrigerant circuit includi ng a cooler and a refrigerant condenser, said circuits having a part in common where the propellant vapor is effective in causing the circulation of the refrigerant, cooling fins disposed about the propellant condenser, and a baflle disposed above the propellant condenser and between a said circuits III - duct portion and the propellant condensers and refrigerant condenser, whereby air heated by the propellant condensers is diverted from rising to the region of the refrigerant condenser, and whereby the duct portion isprotected from direct contact with said heated air.

5. Apparatus of the class described comrisin a ro ellant circuit includin a ro-- pellant vaporizer and apropellant condenser, a refrigerant circuit including a cooler and an air-cooled refrigerant condenser, saidcircuits' having a part in common where the propellant vapor is effective in causing the circulation of the refrigerant, cooling fins disposed about the propellant condenser, and an inclined baflie disposed above the propellant condenser, and between the same and the refrigerant condenser, said baflie having 'a width substantially as great as that of said fins, thereby to divert air heated by the propellant condenser from rising to the region of the refrigerant condenser.

6. Apparatus comprising a refrigerant circuit including a cooler and a refrigerant condenser. and propellant circuits including a vaporizer and separate propellant condensers, said refrigerant circuits and propellant circuits having parts in common where the prol pellant causes the circulation of the refrigerant in successive parts of its circuit, a refrigerant duct disposed between the common parts of the circuits, a portion of said duct being substantially horizontally disposed above the propellant condensers and below the refrigerant condenser, and inclined baffles disposed between said duct portion, and the propellant condensers and refrigerant condenser, whereby air heated by the propellant condensers is diverted from rising'to the region of the refrigerant condenser, and whereby the duct portion is protected from direct contact with saidvheated air.

7. Apparatus of the class described comprising a circuit for a fluid having a relatively high boiling point. said circuit including a vaporizer and condenser, and another circuit for a fluid having a relatively low boiling point, said circuit including a condenser, the circuit'having a part in common where one fluid is effective in causing the circulation of the other fluid, a duct extending upwardlv from the vaporizer and forming a part of the circuit for thefluid of high boiling point and being arranged to contain a column of sa d fluid to balance the vaporizer pressure and to return the fluid to the vaporizer, and means to lift condensed fluid to the top of said column comprising-a reservoir arranged to retain. a supply of the low boiling point fluid, heating means associated be effective in lifting bodies of the condensed fluid in said tube of restricted diameter, the upper end of said tube being connected the duct which returns the heavy boiling point fluid to the vaporizer.

8. Apparatus of the class described comprising a circuit for a fluid having a relatively high boiling point, said circuit including a vaporizer and condenser, and another-circuit, for a fluid having a relatively low boiling point, said circuit including a condenser, the circuits having a part in common where one fluid is effectlve in causing the circulation of the other fluid, a duet extending upwardly from the vaporizer and forming a part of the circuit for the fluid of high boiling point and being arranged to contain a column of said fluid to balance the vaporizer pressure and to return the fluid to the vaporizer, and means to lift condensed fluid to the top of said column comprising a reservoir arrange to retain a supply of the low boiling point vaporizer, said tube being connected to the condenser for the low boiling point fluid, whereby the vapor which flows through the ,tube may be condensed.

9. Apparatus of the class described comprising a circuit for a fluid having a relatively high boiling point, said circuit including a vaporizer and condenser, and another circuit for a fluid having a relatively low boiling point, said circuit including a condenser, the circuits having a part in common where one fluid is effective in causing the circulation of the other fluid, a duct extending upwardly from the vaporizer and forming a part of the circuit for the fluid of high boiling and being arranged to contain a column of said fluid to balance the vaporizer therefrom and to return the fluid to the vaporizer, and means to lift condensed fluid to the top of said column, said means including a secondary vaporizer arranged to receive fluid from the condenser for the low boiling point liquid, said secondary vaporizer including a tube of restricted (liameter, an upwardly extending lifter duct of restricted diameter having its lower end arranged to receive the condensed high boiling point fluid and connected to the secondary vaporizer, whereby the vaporized fluid may lift successive bodies of the high boiling factor,

point fluid in the upwardly extending duct, the upper end of said duct being connected to a trap, the trap being connected to the upper end of the return duct for the high boiling 5 point fluid, the upper end of the lifter duct also having a connection with-the condenser for-the low boiling point fluid.

10. Apparatus comprising a fluid circuit and including a vaporizer having a heating an upwardly extending flue associated with said heating factor, a condenser connected to said vaporizer toefl'ect the liquefication of the vaporized fluid, a return pipe having its upper end disposed above the condenser and arranged to contain a body of the condensed fluid to balance the vaporizer pressure and to return the fluid to the vaporizer, a lifter tube of restricted diameter having its lower end arranged to receive liquid from the 20 condenser and having its upper end connected to the return duct, and means to lift the fluid through said duct comprising a second vaorizer arranged to receive a fluid of lower r oiling point, said vaporizer including an elongate tube of small diameter in heating relation to the flue, said tube having a continuation connected to the lifter tube, whereby the vaporized fluid may break 011' successive bodies of liquid at the lower end of the lifter tube and raise the same to the level of i the upper part of the-return duct.

11. Apparatus comprising a fluid circuit and including a vaporizer having a heating factor, an upwardly extending flue associated 5 with said heating factor, a condenser connected to said vaporizer to effect the liqueflcation of the vaporized fluid, a return pipe having its .upper end disposed above the con denser and arranged to contain a body of the condensed fluid to balance the vaporizer pressure and to return the fluid to the vaporizer, a lifter tube of restricted diameter having its lower end arranged to receive liquid from the condenser and having its upper end connected to the return duct, vapor supply means connected to the lower part of the lifter tube and comprising'a reservoir arranged to receive another fluid of relatively low boiling point and a helical tube of restricted diameter dis osed in heat transfer relation to the flue, said helical tube being connected to the lower part of the lifter tube to permit vpfpor of the low boiling point liquid to break 0 successive bodies of the condenser fluid and to lift the same to the top of the return uct.

12. Apparatus comprising a fluid circuit and including a vaporizer having a heating factor, an upwardly extending flue associated with said heatin factor, a condenser connect ed to said vaporlzer to effect the liquefication of the vaporized fluid, a return pipe having its upper end disposed'above the condenser and arranged to contain a body 'of the con-' densed fluid to balance the vaporizer pressure denser, a lifter and to return the fluid to the vaporizer, a

prising a reservoir arranged to receive a relatively volatile fluid and an elongate duct of restricted internal diameter connected to the reservoir, said elongate duct and reservoir both being in heat transfer relation to the flue, the elongate duct being connected to the lower part of the lifter tube, whereby the relatively volatile fluid is vaporized and passes into the lower part of the return tube to break off successive bodies of the condensed fluid and to lift the same to the upper part of the return duct.

13. Apparatus comprising a propellant circuit including a vaporizer, a propellant condenser, a refrigerant circuit including a cooler and a refrigerant condenser, said circuits having a part in common where propel.- lant vapor is efl'ective in causing the circulation of the refrigerant, a return duct connected to the vaporizer and havin its upper portion disposed above the prope lant condenser a lifter duct connected to the upper portion of pellant thus raised through the lifter duct,

said duct having a restricted internal diameter and being arranged also to receive refrigerant from the refrigerant condenser, a secondary vaporizer, separating means at the lower end of said duct of restricted diameter, said separating means to be arranged to effect the separation of the pro ellant and the refrigerant, a duct arranged to supply refrigerant from the separating means to said secondary vaporizer, the latter being connected to the lifter tube to effect the liftin of sue cessive propellant bodies therein, a duct connected to the separating means and to the lifter tube to supply propellant from the separating means to the lifter tube, said tube of restricted diameter being arranged to receive the condensed refrigerant fromthe lowest part of the refrigerant condenser, and a second duct connected to the condenser above its lowest part and arranged to return condensed refrigerant from the condenser to the cooler,

whereby refrigerant is preferentially supplied to the tube of restricted diameter'and thus to .the secondary vaporizer.

14. Apparatus comprising a propellant circuit including a vaporizer and a propellant condenser, a refri erant circuit including a cooler and a refrigerant condenser, said circuits having a part in common 'where propellant vapor is effective in causing the circulation of the refrigerant, a. return duct connected to the vaporizer and having its upper portion disposed above the propella'nt conduct connected to the upper internal diameter be arranged to effect means at the lower end of said lant vapor is elfective in causing portion of the return duct to supply propellant thereto, a duct arranged to receive a portion of the propellant thus raised through the lifter duct, said duct having a restricted and being arranged also to receive refrigerant from the refrigerant condenser, a secondary vaporizer, separating means at the lower end of said duct of restricted diameter, said separating means to the separation of the propellant and the refrigerant, a duct arranged to supply refrigerant from the separating means to said secondary vaporizer, the latter being connected to the lifter tube to effect the lifting of successive propellant bodies therein, a duct connected to the separating means and to the lifter tube to direct propellant from the separating means to the lifter tube, and a by-pass duct connected to the duct supplying condensed refrigerant to the tube of restricted diameter and connected to the duct receiving propellant from the separating means, whereby refrigerant may be by-passed when the pressure in the secondary vaporizer becomes relatively high.

15. Apparatus comprising a propellant circuit including a vaporizer and a propellant condenser, a refrigerant circuit including a cooler and a refrigerant condenser, said circuit having a part in common where propelthe circulation of the refrigerant, a return duct connected to the vaporizer and having its upper portion disposed above the propellant condenser, a lifter duct connected to the upper portion of the return duct to supply propel- 1antthereto',-a duct-arranged to receive a portion of the propellant thus raised through the lifter duct, said duct having a restricted internal diameter and being arranged also to receive refrigerant from the refrigerant condenser, a secondary vaporizer, separating duct of restricted diameter, said separating means to be arranged to effect the separation of the propellant andthe refrigerant, a duct arranged to supply refrigerant from the separating means to said secondary vaporizer, the latter being connected to the lifter tube to effect the lifting of successive propellant bodies therein, a duct connected'to the separating means and to the lifter tube to direct propellant from the separating means to the lifter tube, a trap connected to the duct which directs the refrigerant from the separating means to the secondary vaporizer, said trap being connected to a duct which is arrange to supply propellant to the lifter tube, whereby stray propellant particles passing to the region of the secondary vaporizer may be collected in the trap, and upon the vaporization of fluid in the secondary vaporizer with increase in secondary vaporizer pressure the,

propellant from the trap may lifter tube.

pass to the tween the upper end 16. Apparatus comprising a refrigerant circuit including a cooler and a refrigerant condenser, a'propellant circuit including a vaporizer and a propellant condenser, said circuits having a part in common where the vaporized propellant is effective in causing circulation of the refrigerant, the refrigerant circuit including a vapor duct between said common part and the refrigerant condenser, a secondary vaporizer, secondary pum ing means arranged to receive refrigerant rom the lower part of the refrigerant condenser and to suppl porizer, a li ter tube of restricted diameter arrangedto receive propellant from the propellant condenserand vapor fromthe secondary vaporizer, apropellant return duct connected to the upper end of the lifter tube and to the propellant vaporizer, a pipe beof the lifter tube and the refrigerant condenser, the connections between the vaporduct and the refrigerant condenser and between the pipe and the refrigerant condenser being disposed at a substantial height above the lowest part of the condenser, and'a duct for returning condensed refrigerant from the refr ger ant condenser to the cooler, the last-named duct being connected to the condenser above its lowest part but below said connections of the refrigerant condenser with the vapor duct and said pipe, whereby condensed refrigerant the same to the secondary vaa is preferentially supplied to the secondary I pumping means and then to the cooler.

17'. Apparatus comprising a refrigerant circuit including a cooler and a refrigerant condenser, a propellant circuit including a vaporizer and a propellant condenser, said circuits having a part in common where the vaporized propellant is effective in causing circulation of the refrigerant, the refrigerant circuitincluding a vapor duct between said common part and the refrigerant condenser, a secondary vaporizer, secondary pumping means arranged to receive refrigerant from the lowest part of the refrigerant condenser and to supply the same to the secondary vaporizer, said secondary pumping means including a tube of restricted diameter wherein propellant globules entrain bodies of refrigerant, a lifter tube of restricted diameter arranged to receive propellant from the propellant condenser and vapor from the secondary vaporizer, a propellant return duct, a vapor pipe between the upper end of the lifter tube and the refrigerant condenser and means receiving propellant from the tube of restricted diameter in the secondary'pumping means and supplying said propellant to a a gropellant circuit including a vaporizer an a propellant condenser, said circuits having a part in common where the vaporized propellant is effective in causing circulation of the refrigerant. the refrigerant circuit including a vapor duct between said common part and the refrigerant condenser, a second ary va rizer, range to recelve refrigerant from the lowest part of the refrigerant condenser and to I supply the same to the secondary vaporizer,

mg said trap sald secondary pumping means including a tube of restricted diameter wherein propellant globules entrain bodies of refrigerant, a lifter tube of restricted diameter arranged to receive propellant from the propellant condenser and vapor from the secondary vaporizer, a propellant return duct, a vapor pipe between the upper end of the lifter tube the refrigerant condenser, resistance means associated with said secondary vaporizer to limit the flow of vapor to the lifter tu a trap receiving propellant from the secondary pumpingmeans, a duct connectto the lifter tube, and a by-pass tween the portion of said trap adjoining the secondary pumpingmeans and the upper end the tube of restricted diameter in said pumping means, whereby pressure building'- up in the secondary vaporlzer will cause refrigerant to be circulated through said by-pass.

19. Apparatus comprising a refrigerant circuit including a cooler and a refrigerant condenser, a propellant circuit including a vaporizer and a propellant condenser, said circuits having 'a part in'common where the vaporized propellant is effective in causing circulation of the refrigerant, the refrigerant circuit including. a vapor duct between said common part and the refrigerant condenser, a secondary vaporizer,-secondary pum ing means arranged to receive refrigerant min the lowest part of the refrigerant condenser and to supply the same to the secondary vaporizer, said secondary pumping means including a tube of restricted diameter wherein propellant globules entrain bodies of refrigerant,-a lifter tube of restricted diameter and ' arranged to receive propellant from the propellant condenser and vapor from the secondary vaporizer, a propellant return duct, a pipe vapor between the upperiend of the lifter tube and the refrigerant condenser, the secondary pumping means including a separating chamber, the tube of restricted diameter in said pumping means havinga vent in the lower partof the chamber, a propellant outlet duct havinga mouth a ve said vent and being arranged to direct propellant to the lifter tube,

ing a mouth above that of the propellant outlet duct and being connected to the secondary vaporizer.

20. Apparatus comprising a refrigerant circuit including a cooler and a refrigerant a secondary pumping means ar-- r denser and vapor and a refrigerant duct hav-v ropellant circuit including a vaporizer an a propellantcondenser, said circuits having a part in common where the vaporized propellant is effective in causing circulation of the refrigerant, the refrigerant circuit including a vapor duct between said common denser, a secondary vaporizer, secondary pumping means arranged to receive refrigerant from the lowest part'of the refrigerant condenser and to supply the same to the secondary vaporizer, said secondary pumping means including a tube of restricted diameter wherein propellant globulesentrainbodies of refrigerant, a lifter tube of restricted diameter arranged to receive propellant from the propellant condenser and vapor from the secondary vaporizer, a propellant return duct, and a vapor pipe between the upper end of the lifter tubea'nd the refrigerant condenser, the secondary pumping means including a separating chamber, the tube of restricted diameter in said pumping means being a vent in the lower part of the chamber, a propellant outlet duct having a mount above said vent and being arranged to supply propellant to the lifter tube, a refrigerant duct having a mouth above that of the propellant outlet duct and being connected to the secondary condenser, a

vaporizer, and a by-pass' between said outlet duct and the upper end-of the entraining chamber, whereupon the development of sufficient pressure in the secondary vaporizer causes propellant to be forced from the vicinity of the mouth of the outlet duct and to flow into the by-pass. I

21. Apparatus comprising a refrigerant circuit including a cooler and a refrigerant condenser, a propellant circuit including a vaporizer and a propellant condenser, said circuits having a part in common where the vaporized propellant is effective in causing circulation of the refrigerant, the refrigerant circuit including a vapor duct between said common part and the refrigerant condenser, 'a secondary vaporizer, secondary pumping same to the secondary' vaporizer, said secondary pumplng means -1I1Cl11d1I1g a tube of restricted diameter wherein propellant glob u es entrain bodies of refrigerant, a lifter of restricted diameter arranged to receive propellant from the propellant confrom the porizer, a propellant return duct, the secondary pumping means including a separating chamber, the tube of restricted diameter in said pumping means being a vent in the lower part of the chamber, a propellant outlet duct having a mouth above said vent and being arranged to supply" tube, and a refrigerant duct having a mouth above that of the propellant outlet duct and being connectedcto the secondary vaporizer.

part and the refrigerant consecondary va-" propellant to the lifter heating means,

' stricted also forming a common part "vided, the pressure balancing and 22. Apparatus of the class described comprising a vaporizer including an elongate tube of restricted diameter associated with an outlet connected to one end of the tube, a liquid supply and pressure bal ancing means connected to the other end of the tube, the amount of liquid in the tube automatically varying in response to increase in vapor pressure, regulation of the amount of vapor passing to its outlet is provided, the pressure balancing and supply means including a tube of rediameter wherein globules of a heavier liquid are normally effective in pumping liquid to said vaporizer and a by-pass arranged to cause short-circuiting of the pumpingmeaus in response to high pressure in the vaporizer.

23. Apparatus of the class described comprising a vaporizer including an elongate tube of restricted diameter associated with heating means, an outlet duct connected to one end of the tube, a liquid supply and pressure balancing means connected to the other end of the tube, the amount of liquid in the vaporizer tube automatically varying in response to increase in vapor pressure, whereby automatic regulation of the amount of vapor passing pp y means including a tube of restricted diameter wherein globules of a heavier liquid are normally effective in pumping liquid to said vaporizer and means associated with said last-named tube to receive the heavier liquid therefrom and permit a column of the latter to bebuilt up to balance initial vaporizer ressure when operation of the apparatus is started and before the globules of heavier liquid are supplied to the diameter.

24. Apparatus of the class described comprising a circuit for a relatively light and volatile fluid, a second circuit for a heavy and less volatile fluid, said first-named circuit including a vaporizerand a condenser,

said circuits having a part in common 1neluding a downwardly-extending tube of re-' stricted diameter wherein globules of heavy fluid entrain bodies of the lighter liquid, se arating means at the lower end of said tu e, a duct connecting said means to the vaporizer, a lifter tube of restricted diameter of said circuits, wherein vapor from the vaporizer lifts globules of the heavier fluid, ducts connecting the lower end of said lifter tube with the vaporizer and the separatin means, ducts c011 necting the upper end 0 condenser and the downwardly extending tube, and a by-pass in parallel with the latter and connected thereto to permit the shortcircuiting'of thelighterfluid which is entrained by the heavy fluid g'lobuleswhen the vaporizer pressure increases.

whereby automatic the vaporizer will cause heayy to the outlet duct is protube of restricted the tube with the tube having an open 25. Apparatus of the class desoribedcomprising a circuit for a relativel light and volatile fluid, a second circuit or a heavy and less volatilefluid, said first-named circuit including a vaporizer and a condenser, said circuits having a part in common including a downwardly extending tube of restricted diameter wherein globules of heavy fluid entrain bodies of the lighter liquid, separating means at the lower end of said tube, a duct connecting said means to the vaporizer, a litter tube ofrestricted diameter also formng a common part of said circuits, wherein vapor from the vaporizer lifts globules of the heavier fluid, ducts connecting the lower end of said lifter tube with the vaporizer and the separating means, ducts connecting the upper end of the tube with the condenser and the downwardly extending tube, the duct connecting the separating means with the lifter tube including a trap containing the heavier fluid and having a leg extending above the separating means, whereby upon starting the apparatus the pressure of fluid to rise in the downwardly extending tube and in said leg of the trap to balance initial vapor izer pressure.

26. Apparatus of the class described comprising a fluid circuit including a vaporizer, a supply duct connected to the vaporizer, a pressure equalizing chamber connected tothe duct, a downwardly extending tube of restricted diameter having an end opening into said chamber below its connection with said duct, the lower part of said chamber contaitping a heavy liquid to seal the end of the tu e.

27. Apparatus of the class described comprising a vaporizer, heating means associate therewith, means for supplying a relatively light liquid to the vaporizer and automatically balancing the vaporizer pressure, said means comprising a downwardly extending tube of restricted diameter receiving globules of a heavy liquid to' entrain bodies of the volatile liquid therebetween, a chamber, the tube having an open lower end immersed in a body of t e heavy liquid in said chamher, a fluid supply duct connecting the chambr to the vaporizer and having an open end in the chamber above the open end of the tube, and a drain for the heavy liquid having a mouth end, but below the duct end.

28. Apparatus of the class described comprising a vaporizer, heating means associated therewith, means for supplying a relatively light liquid to the vaporizer'and automatically balancing the vaporizer pressure, said means comprising adownwardly extending liquid to entrain bodies of the of a heavy a chamber, the

volatile liquid therebetween,

lower end immerse in said chamber above the tube in a body of the heavy liquid in said chamber, a fluid supply duct connecting the chamber to the vaporizer and having an open end 1 tube, a li means comprising a downwar belowthe cham in the chamber above the open end of the one leg of a trap, the other leg ofsaid trap bein provided with a spill-over outlet above thgec amber but below the lowerend of the tu 29. Apparatus of the class described comprising a vaporizer, heating means associated therewith, means for supplying a relatively light liquid to the vaporizer and. automatically balancing the vaporizer ressure, said means comprising a downwar 1y extending tube of restricted diameter receivin globules of a heavy liquid to entrain bodies of the volatile liquid therebetween, a chamber, the tube havin an open lower end immersed in a od of t eheavy liquid in said chamber, a flui supply duct connecting the chamber to the va orizer and having an open end in the cham er above the open end of the tube, and a drain for the heavy liquid having a mouth in said chamber above the tube end, but below the duct end, said drain forming one leg of a trap, the other leg of said trap bein provided with a spill-over outlet about the fiiamber butbelow the lower end of the uid receptacle at the upper end of said tu e having cross-sectional dimensions somewhat greater than the tube so that bodies of the heavier liquid will not form separate globules therein.

30. Apparatus of the class described comprising a vaporizer, heating means associated therewith, means for supplying a relatively li ht li uid to the vaporizer and automaticiil ressure, said ly extending tube of restricted diameter receiving globules a heavy liquid to entrain bodies of the volatile liquid therebetween,

ly ba ancing the vaporizer a bod o t e heavy liquid' in said chamber, a flui supply duct connecting the chamber to the va' ri'zer and having an open end in the cham r above the open end of the tube, and a drain for the heavy liquid having a mouth in said chamber above the tube end, but below the duct end, saiddrain formin one leg of a trap, the other leg of said trap bein provided with a spill-over outlet above the dhamber but below the lower end of the tube and a byass connected to the drain r and communicating with the upper part of the tube, whereby high vaporizer pressure forces the lighter-liquidthrough the chamber and the upper the,drain into the by-pass.

31; Apparatus of the class described comprising a vaporizer, heating means associated therewith, means for supp ying a relgtively volatile liquid therebetween,

a chamber, the. tube havnglan open lower end immersed in part of li ht liquid to the vaporizer and aut0matica ly balancing the vaporizer pressure, said means comprising a downwardly extending tube of restricted of a heavy liquid to entrain bodies of the tube havin an open lower end immersed in a bod of t e heavy liquid in said chamber, a flui supply duct connecting the chamber to the va orizer and having an open end in the cham er above the open end of the tube, and a drain for the heavy liquid having a mouth in said chamber above the tube end, but below the one leg of a trap, the other leg of said trap bein provided with a spill-over outlet about the-c amber but below the lower end of the tube, a liquid receptacle at the up er end of said tube having cross-sectional 4 somewhat greater than the tube so that bodies of the heavier liquid will notform separate globules therein and a by-pass connected to the drain below the chambe e upper part of the tullile, t e' r and communicating with th whereby high vaporized pressure forces lighter liquid through the chamber and the upper art of'the drain into the by-pass.

32. pparatus of the class described comprising a vaporizer, heatin means associated therewith, means for suppqying a relativel light liqu cally ba ancing the vaporizer ressure, said means comprisin a downwar y extending tube of restricte diameter receiving globules of a heavy liquid to entrain bodies of the volatile liquid t-herebetween, a chamber, the tu having an bpen lower end immersed in a body of the heavy liquidin said chamber, a fluid supply duct connecting the chamber to the va orizer and having an open end in the cham erabove thd open end of the tiibe, and a drain for .the heavy liquid having a mouth in said c amber above the tube end, but below the not end, an elongat outlet passage ofrestricted to the vaporizer and afl'ordin rapid vapor fl whereby. the vaporizer rise inresponse to an increase in rate of vaporization.

33. Apparatus of the class described commeans associated the with, means for su li Ii 11 PP c lybiilancing the vaporizer ressure, said means comprisin a downwardly extending tube of restricte diameter receiving glob; ules of a heav liquid to entrain bodies of the volatile liqui therebetween, a chamber, the tu having an open lower end immersed in a bodgof the heavy liquid in said chamber, a flui supply duct connecting the chamber th the va orizer and having an open end in the cham erabove the open end of the tube, nd heavy liquid having a a a drain for the mouth in said chamber about the tube end,

diameter receiving globules a chamber, the

id to the VHPOI'IZGI' and automatiimensions v cross-section connected g resistance to idfto the vaporizer and automati- 

